RFR: 8307058: Implementation of Generational ZGC [v3]

[Martin Doerr]

On Thu, 4 May 2023 09:50:23 GMT, Axel Boldt-Christmas <aboldtch at openjdk.org> wrote:

>>> I'm getting build warnings on all linux platforms with gcc-11.3.0:
>>> 
>>> ```
>>> src/hotspot/share/gc/z/zDriver.cpp:84:13: error: In the GNU C Library, "minor" is defined
>>>  by <sys/sysmacros.h>. For historical compatibility, it is
>>>  currently defined by <sys/types.h> as well, but we plan to
>>>  remove this soon. To use "minor", include <sys/sysmacros.h>
>>>  directly. If you did not intend to use a system-defined macro
>>>  "minor", you should undefine it after including <sys/types.h>. [-Werror]
>>>    84 | ZDriverMinor* ZDriver::minor() {
>>> ```
>> 
>> That's unfortunate as minor and major are quite central to Generational ZGC and having to rename those functions will make the code look worse. I wonder if we should undef minor and major where needed.
>
>> I'm getting build warnings on all linux platforms with gcc-11.3.0:
>> 
>> ```
>> src/hotspot/share/gc/z/zDriver.cpp:84:13: error: In the GNU C Library, "minor" is defined
>>  by <sys/sysmacros.h>. For historical compatibility, it is
>>  currently defined by <sys/types.h> as well, but we plan to
>>  remove this soon. To use "minor", include <sys/sysmacros.h>
>>  directly. If you did not intend to use a system-defined macro
>>  "minor", you should undefine it after including <sys/types.h>. [-Werror]
>>    84 | ZDriverMinor* ZDriver::minor() {
>> ```
> 
> @TheRealMDoerr I cannot reproduce this with gcc but can see the issue with clangd.
> Can you check if this patch solves the issue you are seeing?
> 
> diff --git a/src/hotspot/share/gc/z/zDriver.hpp b/src/hotspot/share/gc/z/zDriver.hpp
> index 640ea6575ef..7fa650b1fa1 100644
> --- a/src/hotspot/share/gc/z/zDriver.hpp
> +++ b/src/hotspot/share/gc/z/zDriver.hpp
> @@ -29,6 +29,14 @@
>  #include "gc/z/zThread.hpp"
>  #include "gc/z/zTracer.hpp"
>  
> +#ifdef minor
> +#undef minor
> +#endif
> +
> +#ifdef major
> +#undef major
> +#endif
> +
>  class VM_ZOperation;
>  class ZDriverMinor;
>  class ZDriverMajor;

@xmas92: Thanks for your quick solution. Your patch solves the problem. If you want to integrate it, please also add a comment why this is needed.

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PR Comment: https://git.openjdk.org/jdk/pull/13771#issuecomment-1534563624